The invention relates to a method for the realization of printed decorations on elongated elements, in particular rigid materials having the shape of a section bar.
In the known art methods are known for the realization of decorations on section bar elements for doors and windows which comprise the utilization of decorative transferable elements that are heat applied on the surface of a section bar element. The decorations that can be obtained through the use of such known methods have a low definition degree, as the decorative elements are transferred by sublimation from a support whereon they are applied in advance to the section bar to be decorated.
Besides, these methods involve high costs, due to the high cost of the decorative transferable elementsxe2x80x94which must be preliminary obtained on a service support wherefrom they are subsequently transferredxe2x80x94and the necessity to have ovens or other heating systems suitable to contain the section bars during the sublimation of the decorative elements from the original service support.
Besides, with such methods it is difficult to decorate the surfaces of a section bar located in a marked depression or rise with respect to a face of the section bar acting as a reference plane.
It is also known how to decorate surfaces employing spray or ink jet devices provided with computer-controlled head or printing unit, and able to move along three axes orthogonal with respect to the surface to be decorated, which is kept in a fixed position. The printing head or unit is provided with nozzles through which a decorating substance is dispensed to be applied on the surface to be decorated.
With the use of such devices, it is possible to decorate substantially flat surfaces, bent surfaces having a high bending radius or also surfaces that develop on different planes, with moderate differences in height between said different planes. On the contrary, with the above decoration system it is not possible to make decorations on surfaces with a small bending radius, on surfaces that develop on planes different from each other, in particular when great differences in height exist between said different planes, nor on surfaces having a complex form. In said cases, in fact, it is not possible to maintain the spray or jet of the decorating substances projected by the printing unit in a direction substantially perpendicular to the surface to be decorated, in all the points of said surfaces, with the consequence that in the zones with a small bending radius or in the surfaces bridging different levels decoration systems for elongated elements, in particular section bars.
A further object of the present invention is to provide a system for the realization of decorations on elongated elements such as to allow the decoration of surfaces of such elements having a complex section profile, showing in particular high level alterations.
In a first aspect, the present invention provides a method for the realization of printed polychrome decorations on elongated elements through a plurality of jets of dyeing substances that are projected by the respective nozzles towards external surface zones to be decorated of said elements, characterized in that during the printing a substantially constant distance is kept between said zones and said nozzles, also in correspondence of profile variations of said zones.
In a second aspect, the present invention provides an apparatus for the realization of printed polychrome decorations on elongated elements, said apparatus comprising support means for said elongated elements, decorating means suitable to project, through the respective nozzles, a plurality of jets of dyeing substances towards external surface zones to be decorated with said elongated elements, characterized in that it also comprises distance measuring means suitable to measure the distance between said nozzles and said external surface zones and positioning means functionally associated to said distance measuring means, to position said nozzles with respect to said external surface zones.
Keeping a substantially constant distance between the nozzles dispensing the dyeing substances and the zones to be decorated allows to optimize the graphic definition of the decoration and to maintain it substantially equal throughout the decorated surface.
In a third aspect, the present invention provides an elongated element provided with decoration zones on its external surfaces, characterized in that said decoration zones have sharp outlines.
In a fourth aspect, the present invention provides an elongated element provided with decorations on zones of its external surface, characterized in that said decorations are realized with various dyeing substances, such as liquid substances, liquid suspension substances, powders or sublimable inks.
The elongated element subject matter of the present invention is selected, for instances as a metal section bar, for instance from aluminum, of big size, having in particular a length of up to 20 meters.